Richard M. Felder
Department of Chemical Engineering
North Carolina State University

Phil Wankat wrote somewhere--and I agree--that anything you can
do in a large class you can do better in a small one. When we
find ourselves teaching a mob, it's easy to throw up our hands,
conclude that there's no chance of getting any responsiveness
out of 150 or 300 students in an auditorium, and spend 45 hours
showing transparencies to the listless 60% who bother to show
up from day to day. We can generate some interest by bringing
demonstrations to class, but there are only so many hydrogen balloons
we can explode and even they lose their impact after a while.

Fortunately, there are ways to make large classes almost as effective
as their smaller counterparts. Without turning yourself inside
out, you can get students actively involved, help them develop
a sense of community, and give frequent homework assignments without
killing yourself (or your teaching assistants) with impossible
grading loads. Following are some ideas for doing all that.

In-Class Exercises

Lectures as a rule have little educational value. People learn
by doing, not by watching and listening. If you're teaching a
small class and you're good, you may be able to prod many of your
students into activity--get them asking and answering questions,
discussing issues, challenging conclusions, laughing at your jokes,
whatever. No matter how good you are, though, you probably won't
be able to persuade most students to open their mouths in front
of 120 classmates--it feels too risky for them. If you hope to
move away from the wax museum-like aspect of most large lectures,
you'll have to try a different approach.

A technique you can count on is the in-class exercise. As you
lecture on a body of material or go through a problem solution,
instead of just posing questions to the class as a whole and enduring
the ensuing time-wasting silences, occasionally assign a task
and give the students anywhere from 30 seconds to five minutes
to come up with a response. Anything can serve as a basis for
these exercises, including the same questions you normally ask
in lectures and perhaps some others that might not be part of
your current repertoire.1 For example,

Using terms a bright high school senior (a chemical engineering
sophomore, your grandmother) could understand, briefly explain
the concept of vapor pressure.

Why does it take much longer to prepare a hard-boiled egg
at a ski resort than at the beach?

Estimate the rate of heat input to a kettle on a stove.2

On the last homework, one student reported a required tank
volume of 3.657924x106 m3.
Name at least two things wrong with this result

You might pose a problem or describe a system and ask the students,
individually or in groups, to

In these exercises you might sometimes ask the students to write
responses individually, sometimes to work in pairs or groups of
three, and sometimes to work alone and then to form pairs and
combine and improve their individual responses ("think-pair-share").
The more you vary your methods, the more interesting the class
tends to be.

Whichever approach you use for the exercises (individual,
pairs, groups, or think-pair-share), at least some of the time
you should call on groups or individuals to present what they
came up with, perhaps landing disproportionately on students
near the back of the room so they know they can't hide from you
there. If you never do this, students will have little incentive
to work on the exercises when you assign them and many won't,
but if they think they may be called on, they won't want to be
embarrassed and so you'll get 90+ percent of them actively involved
in what you're teaching. Even if you're an award-winning traditional
lecturer, that's probably better than your usual percentage for
active student involvement during class.

The principal benefit of these exercises is that they get students
acting and reflecting, the only two ways by which human beings
learn. The students who succeed in a task will own the knowledge
in a way they never could if you simply handed it to them, and
those who try and fail will be receptive to discovering what they
didn't know. Group exercises have the added benefit of giving
students an opportunity to meet and work with one another, a good
first step toward building a sense of community. (You can augment
this benefit by periodically asking the students to sit in different
locations and work with students they haven't been with before.)

You can also use in-class exercises to wrap up a lecture period.
Ask the students to write down and hand in a brief statement
of the main point of the lecture, or come up with two good questions
or test problems related to what you just presented, or tell you
how they think you could improve the class. You can scan their
responses and quickly see if they got the main idea you were trying
to present, identify their main points of confusion, or discover
things you could do that would make the class better for them,
like giving more examples or leaving material on the board longer
or speaking more slowly or not cracking your knuckles every five
seconds.

You don't have to spend a great deal of time on active learning
exercises in class: one or two lasting no more than five minutes
in a 50-minute session can provide enough stimulation to keep
the class with you for the entire period. The syllabus is safe!

Out-of-class Group Assignments

When you're teaching a class of 160 students and you give individual
homework weekly, that's 160 papers to grade every week. If the
students complete the assignments in teams of four and only one
solution is handed in by each team, that's 40 papers to grade
every week. The difference has a major impact on the feasibility
of collecting homework at all. Unless you have a squadron of
teaching assistants, there is no good way to deal with 160 papers
every week, and most instructors in this situation either give
up on collecting homework (which is a pedagogical disaster), confine
themselves to multiple-choice problems that require either memorization
or rote substitution, or grade superficially enough for the homework
to lose most of its educational value. Even if there are enough
teaching assistants to do the job, maintaining quality control
on the grading of hundreds of assignments is next to impossible.

Getting students to work on assignments in fixed teams relieves
the grading problem but introduces another set of problems, most
of which have to do with the fact that the students in a group
may have widely varying levels of ability, work ethics, and senses
of responsibility. If an instructor simply tells students
to get into groups and do the work, more harm than good may result.
In some groups, one or two students will actually do the work
and the others will simply go along for the ride. In other groups,
the students will parcel out the work and staple the individual
products together, with each student understanding only one-fourth
of the assignment.

To minimize the likelihood of these situations occurring, the
instructor must structure the assignments to assure that the defining
conditions of cooperative learning3 are met:
(1) positive interdependence (if one team member fails
to meet his or her responsibilities, everyone loses in some way);
(2) individual accountability (each student is held personally
accountable for his or her part and for everyone else's part as
well); (3) face-to-face interaction, at least part of the
time; (4) development and appropriate use of teamwork skills
(leadership, time management, effective communication, and conflict
resolution, to name a few), and (5) periodic self-assessment
of group functioning (What are we doing well as a group? What
do we need to do differently?)

Books, articles, and workshops abound that describe techniques
for achieving the requisite conditions of cooperative learning.3-5
For example, individual accountability is promoted by testing
individuals on all of the material covered in group assignments
and by factoring individual effort assessments into team project
grading. Positive interdependence is fostered by assigning rotating
roles to team members (coordinator, recorder, checker), and by
offering small bonuses on tests to all members of teams with average
test grades above (say) 80. References 3-5 offer many other suggestions.

Miscellaneous Ideas

Put your policies and procedures for grading, attendance,
late homework, missed tests, etc., in writing, and hand them out
on the first day. Making up the rules as you go along is never
a good idea, but it can be disastrous in a large class.

Learn as many of the students' names as you can. If you have
250 of them to deal with and you're not a mentalist, it may not
be worth the effort to try learning them all; however, if the
class is small enough to justify the attempt, tell the students
to sit anywhere they want to on the first day and remain there
in subsequent classes. Then prepare a seating chart and study
it during tests and when the students are working on in-class
exercises. Also think about taking and labeling photographs and
studying them out of class.

Prepare handouts far enough ahead of time to make sure that
they will be ready for the class in which they will be used.
Telling a secretary at 9:30 a.m. that you need 275 copies of
a six-page document printed front-and-back in time for your 10:00
class is not a good way to win friends and influence people.

After you have taught the course enough times to be comfortable
with your lecture notes, consider having them duplicated and bound
by a commercial photocopier and sold as coursepacks, thereby saving
your department hundreds or thousands of dollars in photocopying
costs. Leave gaps in the notes to be filled in during class or
by the students in or out of class, sprinkle the notes with questions
about the contents, promise the students that some of the gaps
and questions will show up on the tests, and keep your promise.
The students will then actually read the notes. (Some of them
will, anyway-at least after the first test.)

If you hand out notes or provide a coursepack, don't spend
the lecture hours simply going over all the derivations, explanations,
etc., for the students to follow along. You're guaranteed to
put them to sleep like that. Instead, use the time to go over
the conceptually difficult points, provide additional examples,
fill in some of the gaps and answer some of the questions in the
notes, and carry out some of the active learning exercises described
earlier.

If homework sets are handed back in class, get the TA's or
secretary to stack them alphabetically and start them in the back
row of the classroom at the beginning of the period. The students
will be able to find their papers quickly and pass the stack along,
and left-over papers will end up in the front where you can easily
pick them up at the end of class.

Announce your office hours and hold to them, making it clear
to the students that you are not available as a round-the-clock
consultant to help them with homework problems (as opposed to
real emergencies). Setting your boundaries is always good practice,
but it may be critical to your sanity if you have really large
classes and a reputation for accessibility.

To minimize the number of times you have to answer the same
questions, encourage students to come to your office hours in
groups and invite students waiting in the hall to come in. Also
encourage students to send questions via e-mail, and if you find
yourself answering the same questions repeatedly, create an FAQ
(frequently asked questions) file with your responses and insert
it in subsequent replies. (You could also print it out and post
it.)

Publish your test dates at the beginning of the semester.
Consider giving only one comprehensive make-up test near the
end of the semester for students who miss any of the tests during
the semester, rather than one for each test.

If a test is not multiple-choice and will be graded by teaching
assistants, have a grading party soon after the papers have been
collected so that the grading can be completed and the papers
returned to the students reasonably quickly. (Pizza and soft
drinks will be greatly appreciated-you can afford it.) Make up
a thorough solution key, spelling out in as much detail as possible
how partial credit should be assigned. Go over the key with the
graders, making sure they understand what you have in mind. (If
grading in a large class is sloppy or inconsistent, the subsequent
parade of disgruntled students can be endless.)

Make sure that each part of an assignment or test is graded
by only one grader so you don't have to deal with two students
getting different grades for the identical response. Encourage
the TA's to consult with one another and with you about responses
that are difficult to grade.

Prepare spreadsheets for recording homework and test grades.
You'll be very glad you did when the final grades have to be
computed, especially when a necessary correction is discovered
that requires refiguring averages. If a TA maintains the grade
spreadsheet, have him or her get you a copy each time additions
or revisions are made. If you change a grade, send word of the
change (both the old grade and the new grade) to the responsible
TA, get a confirmation, and keep a record of all requests in case
of a communication breakdown.

Summary

Teaching a large class effectively is hard work, but it's
possible to do it even if you're not a big-league entertainer.
If you make the necessary logistical arrangements far enough
in advance, provide plenty of active learning experiences in the
classroom instead of relying on straight lecturing, and take full
advantage of the power of teams in both in-class and out-of-class
work, large classes can come close to being as educationally rewarding
as small classes. The instructor's satisfaction may be even greater
in the large classes: after all, many professors can teach 15
students effectively, but when you do it with 100 or more you
know you've really accomplished something.

RICHARD M. FELDER is the
Hoechst Celanese Professor of Chemical Engineering at North Carolina
State University. He is co-author of the introductory chemical
engineering text Elementary Principles of Chemical Processes
and codirector of the National Effective Teaching Institute.